This invention relates to a dual brush floor sweeper.
Floor sweepers having one or more rotatable brush rollers for sweeping debris into an adjacent dust pan have long been known. Although commonly called carpet sweepers, in recent years these devices have been developed to the point where they function very adequately on smooth floors as well as carpets. See, for example, U.S. Pat. No. 3,457,575 entitled "Sweeper For Carpeted And Smooth Floors".
It has always been desirable to provide a floor sweeper having the highest pickup efficiency possible so that a minimum of debris remains on the floor surface after several passes of the sweeper thereover. While two brush rollers are better than one in this respect, and while improvements in brush construction and drives have been made over the years, both small debris such as thread and sand, and large debris such as cigarette butts still occasionally remains behind on the floor.
It is a task of the present invention to provide an improved floor sweeper wherein the action thereof tends to increase the pickup efficiency as compared to presently known sweepers, without having to resort to the use of vacuum.
The broadest aspect of the invention is based on the discovery that a sweeper having two brush rollers, each having different pickup characteristics, tends to have an overall increased pickup efficiency as compared to a dual brush sweeper wherein the brushes have the same characteristics.
In accordance with another aspect of the invention, one of the brush rollers is of a type which tends to pick up larger size debris than the other brush roller, so that the brush rollers tend to compliment each other. One of the brush rollers may have a different type of bristle or tuft configuration than the other. Also one of the brush rollers may have a different type of rotating action than the other.
In accordance with a further aspect of the invention, the brush roller which tends to pick up larger debris may be positioned at the front of the sweeper to lessen the chance for the other brush roller to clog.
In accordance with a more detailed aspect of the invention, the front brush roller is provided with flicking type off-center bristle tufts and is adopted to rotate continuously toward its pan during both fore and aft reciprocal translation of the sweeper over the floor. The front brush roller free wheelingly rotates toward its pan at about 21/2 times ordinary rolling rotation on the floor during forward sweeper movement, and is driven in the same direction during rearward sweeper movement. The rear brush roller is of the wire twist type with closely arrayed non-tufted bristles, and rotates toward its pan by freely rolling on the floor when the sweeper is moved in one direction, and is driven when the sweeper moves in the opposite direction.